Hubby How To: DIY Planter Box

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Have you ever wanted a beautiful long planter box to grow veggies, herbs or plants in?! We needed one for our deck, so we could up our food/herb production. This let us grow our own food that we then wouldn’t have to get from the grocery store…and nothing gets wrapped in plastic here, which is a bonus! We loved how our DIY Planter Box turned out and want to share with everyone! Here’s the tools, materials, and how-to to build your own DIY planter box too!

Updated 2/15/2022

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All you need is something to cut wood, and something to screw it back together. If you’ve got that, you’ll be growing veggies in your DIY Planter Box in no time!  

DIY Planter Box

Tools You Will Need:

  • Miter Saw (Preferred, but  you can made do with other options)
  • A Tape Measure
  • Drill
  • Speed Square

First, go grab our printable drawing package for these planter box plans from our Shop or Etsy Shop, if you prefer. These drawing plans outline all the materials and assemble of this DIY planter box.

I recommend a Miter Saw to make the cleanest cuts for the corners and because it speeds up the cutting process. If you have a table saw, hand held circular saw or jig saw with an adjustable guide/blade you’ll still be able to cut the mitered corners. It will just take a steadier hand and some patience. If you don’t have a good tool for cutting mitered corners, you can make straight cuts instead, but you’ll have to remember to subtract the material thickness from the length of one of the boards at each end. We’ll get into that more when we get to the cutting step. 

For now, if you are looking to buy a Miter Saw, I highly recommend getting a sliding one so you can cut wider boards when you need to. The saw I own is from WEN Miter Saw, and you can find their products on Amazon.

If you don’t already own a drill, do yourself a favor and buy a drill. Name brand drills like Dewalt can run up to around $100, but if you shop around on Amazon you can find well reviewed 20v Cordless Drills for under $40 that will get the job done. 

Planter Box Materials

Materials & Costs:

Materials and cost will vary depending on how long you want your DIY planter box to be and wood type you choose. Below are some examples:

DIY planter box materials and costs list

*Note the material prices will fluctuate based on where you’re located and what’s currently going on with the construction market. The table above reflects updated prices to date, but I expect they’ll continue to change as time goes one.

You will also need Paint, Stain, or Oil to finish the boards.

The Wood

The cheapest option is to use Common Boards, which typically comes from soft pine. They don’t generally hold up as well in the long run, but are still usable for outdoor projects when stained and sealed or painted. Be sure to look over every board to make sure it is straight and free of splits. 

A slight step up is Select Pine. These are generally straighter and prettier than Common Boards, so choose these if you intend to stain the boards, but still want a cheaper option.

A good option for outdoor use is Pressure Treated Wood. Pressure Treated Wood that was treated with chromated copper arsenate was banned by the EPA in 2003 due to concerns that arsenic could leech from these boards and into the soil where it could be absorbed by plants. Nowadays, Pressure Treated Wood is typically treated with alkaline copper quat (ACQ) and copper azole (CA-B). There are still concerns that copper could leech from these boards, which is why they aren’t recommended for use where food will be grown. Some studies conclude that by the time the plants absorbed enough copper to be harmful to humans, the plant would have died anyway.

If you do decide to use Pressure Treated Wood for your planter boxes and plan to grow food, then you may consider using a plastic liner. Just make sure you poke holes in the bottom to allow for drainage. If you want to avoid using plastic, (as we try to on this blog!) then the next most effective options are an opaque Polyurethane Floor and Deck Enamel or a Solid Color Acrylic Deck Stain. You can read this article for more information from the The Connecticut Agricultural Experiment Station. 

The final option is to use a naturally rot resistant option like Cedar. This wood typically costs more than the previous options, but it looks beautiful when stained or oiled and will hold up for years to come. We decided to go with this option for our Planter Boxes! We took it one step further and coated them with Spar Urethane to seal them. This means they don’t need re-oiled. If you decide to do this as well, ensure that your Spar Urethane cures completely before adding any soil. 

Earth

The gravel will go into the bottom of our Planter Box to help the soil drain. No need to buy anything nice for this. Just pick the cheapest stuff you can find. You’ll want larger gravel to go in the bottom and then pea gravel on top.

As for the soil, you can go with either potting soil or garden soil. While potting soil may be specially formulated for containers, the soil is extremely processed compared to garden soil and costs quite a bit more. We chose to go with garden soil for our planters.

Screws

For screws, you are going to want to go with something exterior rated. We will be using the Deckmate brand of our project. Other important things to look for though are the drive and the threads. I highly recommend getting screws with the Torx Star Drive over the typical Phillips head. The star pattern grips well and I haven’t had one strip out yet. The same can’t be said for Phillips heads. As for threads, I prefer screws that have serrated threads that cut their way into the wood so you don’t have to pre drill a hole and they are much less likely to split the wood as they go in as well. This saves you a lot of time and headache in the long run.

Finishes

Finally, you’ll need some kind of finish for your planter box. If you picked cedar then I recommend oiling your wood with linseed oil or mineral oil. Be Careful! Boiled linseed oil generally has chemicals added to help it dry faster that could leech into the soil. You’ll want a raw linseed oil or a chemical free boiled linseed oil (sometimes called Double boiled).

If you went with pine, but want to stain it, then be sure to do your research and find a natural stain. Then consider sealing the boards with nautical polyurethane or “spar urethane”. If you want to paint your boards, then be sure to pick a brand of exterior paint with Low VOC.

Alright! Time to Start!

Wooden DIY planter box sitting on workshop counter
DIY Planter Box Completed

DIY Planter Box – Step by Step How To:

Cutting the Wood

  1. Start by purchasing a copy of our printable drawing package with detailed plans. This will give you all of the dimensions and quantities you’ll need along with step by step assembly instructions!
  1. Layout your boards and determine which ones are the best looking, then separate them out. The worst looking 1×6’s will be our bottom boards and the worst looking 1x4s will be our internal support structure.
  2. Measure and Mark your cut lines for the straight cuts on your boards. If one of the ends is damaged or has a large knot, try to make that the end that you cut off.
    • The measurements provided assume that the corners you cut are mitered corners. If you choose to make only straight cuts instead, then you’ll need to remove the material thickness of a board from the length of one board at each corner. 
    • For example, If you choose to do straight cuts for the siding and want to leave the front and back boards the full length, then you’ll need to shorten the side boards. So rather than being 18” long with mitered corners they would be 18” – 0.75” – 0.75” = 16.5” long with straight cut corners.
  3. Line up your miter saw blade with the cut lines being sure you check where the teeth of the blade will remove material. That ⅛” can add up and throw you off when it’s time to assemble.
DIY planter box drawing package sheets laying on workbench
Printable Drawing Package
DIY planter box boards laying on ground
Decide which boards look the best
Measuring the DIY planter box boards before cutting
Measure twice cut once!
Lining up the edge of the saw tooth with your cut line to be as precise as possible for the planter box
Line up the edge of the saw tooth with your cut line to be as precise as possible

HUBBY TIP: Since we’ll be cutting a lot of the boards to the same dimension or the internal structure, a time saving tip is to line up the first board and clamp it in place on the miter saw. Then position some scrap wood at the end of your board and clamp it in place to create a back stop. When loading the next board, you just slide it to the back stop and cut. No need to remeasure for each one!

Using backstop with saw
Use a Backstop to speed up repetitive cuts!
  1. Make all of your straight cuts.
all the cut boards and mitered corners marked
All the cut boards with mitered corners marked
  1. Now for the trickier part. The miters! We’ll start with the side boards. Rotate your saw to 45 degrees and lock it in place.
  2. Align your board so that the edge of the saw blade contacts the upper edge of your board. Clamp the board in place and cut your mitered edge. Be careful when cutting at these angles to keep your hands out of the path of the saw. 
  3. Cut the Mitered edge on all of your siding pieces.
cutting the mitered edges for the planter box
Cutting the mitered corner for the side boards
cutting the mitered edges for the planter box
Cutting the mitered corner for the top boards
  1. Use your speed square to mark the cuts for the mitered corners of your top pieces. 
  2. Rotate your saw back up to it’s vertical (0 degree) position and then rotate the base to it’s 45 degree position.
  3. Align your blade up with the line on your boards and cut your mitered corners.
  4. That’s it! You’ve cut all your wood! Now vacuum up that saw dust and give yourself a pat on the back! No really…pat yourself off. You’re probably covered in dust.
Stack of lumber with mitered corners
All the mitered corners cut!

Finishing the Boards

  1. Before we assembly the planter boxes, we’ll want to finish the boards. It will be hard to get into all the nooks and crannies once it’s assembled and we want to make sure to fully protect the boards.
  2. We discussed finishes up above, so choose your favorite option and coat the boards, then take a second to admire how pretty they turned out. Actually, take multiple seconds because you’ll need to let your coatings dry/cure.
  3. Be sure to get both sides of the boards and the ends as well.
  4. If your coating requires a second coat, or you are doing stain/oil and then spar urethane, then go ahead and put that second coat on now and let it dry.
  5. For some coatings, they’ll be workable long before they’re fully cured. If it’s dry enough to touch, then go ahead and move on to the next step!
Colorful old sock on a gloved hand ready to apply wood oil
Putting an old sock on your gloved hand makes staining/oiling boards a lot easier

Assembly

  1. It’s all coming together. Or at least, it will be soon! Assuming you got our printable drawing package, you’ll have step by step assembly instructions already.
  2. First thing you’ll want to do is assemble the support structure pieces. Start all the screws in your uprights and then lay the piece onto the table top to keep them flush and square when screwing everything together. 
Screw together your Planter Box Support Structures
Screw together your Planter Box Support Structures

HUBBY TIP 2: The screws we bought will drill themselves into the wood easily enough, but when you are driving in screws right next to the edge of a board, it is still helpful to pre-drill a ⅛” hole to help keep the boards from splitting. 

  1. Once you have all of your support pieces assembled, you’ll want to stand them up on a table upside down. We’ll be attaching the bottom boards next.
  2. Start the screws into your bottom boards and then place them onto the support structures.
  3. Align the edges of the bottom boards with the support structure and screw everything together.
Bottom Boards Screwed to the Support Structure
Bottom Boards Screwed to the Support Structure
  1. Now it’s time to destroy your work. It’s a small destruction though. I promise. We’re going to drill a series of ⅜” – ish holes into your bottom boards so that water can drain out of the planter box more easily.
predrilled holes in wood boards
3/8″ Hole every 6-ish inches
  1. Flip your planter box body over, it’s time to start putting together the siding.
  2. If you stained your boards, take a minute to decide what order you’d like the piece to go together and lay them out so that their grain pattern makes you happy. Or if you’re the hubby who got assigned this project, call your wife over and let her choose what makes her happy. I get it right about 80% of the time, but I’d rather she be happy 100% of the time 🙂
  3. Lay your bottom most piece of front siding against your box frame along with a side piece. 
  4. Align the edges of your mitered corners and press them against your upright to keep everything square.
  5. Drill a pilot hole for your screw. 
drilling pilot holes for the corners
Drill pilot holes when near the corners
  1. Compare the head of your screw to your drill bits to find one that’s about the same size and then use that to remove some material around the pilot hole. This will help the screw sink in and be more flush without crushing into the wood and possibly splitting it. This step isn’t normally necessary, but since we are right on the edge of the board, you’ll want to take this precaution.
Using a larger pit to remove material so that sinking your screw doesn't split your board
Use a larger pit to remove material so that sinking your screw doesn’t split your board
  1. Screw your boards together.
  2. Repeat this for the other side piece, and then repeat again for the back piece. Tada! Now you have a box!
Screw all four Mitered Corners together

HUBBY TIP 3: You’ve probably noticed that there are some gaps in the corners. This is from either not having your angle set perfectly, there being some warping in the wood, or any number of other factors. The easy fix is to take a round piece of metal and run it along the edge of the mitered corner. This will compress the wood together and fill in any gaps.

Use a round piece of metal to compress your mitered edges and close up any gaps
Use a round piece of metal to compress your mitered edges and close up any gaps
  1. Repeat these steps two more times to get all the layers of the planter box.
  2. Now screws these boxes into your support frame.
  3. Place your Top Cap strips on to the box, align the corners, and screw them down.
  4. Look at that! You’ve got yourself a planter box!
Wooden DIY planter box on workshop counter
Fully Assembled DIY Planter Box

Time to fill it up!

  1. Assuming your car and your back survived the trip to the store to buy all the soil and rocks you needed, it’s time to fill up your Planter Boxes!
We built two planters at once….so the car was PACKED!
  1. I recommend you finalize where you would like to put the planter before you start dumping rocks and soil in it, because it likely won’t be moving for a while. Also, if you choose to put these on your deck like we did, make sure you are putting them over the main support structure of your decks so that their weight is transferred as directly to the columns as possible. These planters will weigh a few hundred pounds by the time we’re done.
  2. Make sure that your planter’s coating cure fully before you put any soil into them.
Make sure to put your planter in it’s final location before filling up….it gets WAY TOO HEAVY!
  1. Pour in your large gravel and spread it out evenly.
  2. Pour in your pea gravel and try to spread it out without mixing it into the larger gravel below. These two layers will allow excess water to drain from your soil and out of your planter box more easily.
  3. Pour in all your dirt!
  4. Lastly, plant all the wonderful herbs, veggies, or whatever!
Time to fill up the planter!
Our little guy sure loves you help! Get your family or friends involved!
Smaller rock layer goes next
Then add some soil
Last, add your plants!

That’s it! You’re done! You did it! You’ve got a beautiful DIY planter box that is ready for planting! Congratulations!


Let us know how your DIY Planter Box turned out and share your tips in the comments! We love to hear from others and are always looking to improve!

Disclaimer: This post includes affiliate links, and I will earn a commission if you purchase through these links. Please note that I’ve linked to these products purely because I recommend them and they are from companies I trust. There is no additional cost to you.

Yield: (1) 96" long planter box

Hubby How To: DIY Planter Box

DIY Planter Box

Hubby's How-To instructions to build your own 96" long planter box!

Materials

  • (x11) 1x6x96 Boards
  • (x6) 1x3x96 Boards
  • 1 lb - 1 ¼” Screws
  • 2.5 Cubic Feet of Larger Gravel
  • 1.5 Cubic Feet of Smaller Gravel
  • 10.5 Cubic Feet of Garden Soil

Tools

  • Miter Saw (Preferred)
  • A Tape Measure
  • Drill
  • Speed Square

Instructions

  1. Choose your type of wood
  2. Cut wood per the dimensions in our Printable Drawing Package
  3. Stain/Seal/Paint the boards using an Environmentally Safe Option.
  4. Assembly the planter box.
  5. Move the planter box to its final location.
  6. Add large rocks
  7. Add small rocks
  8. Add soil
  9. Add plants
  10. Enjoy your the beautiful planter and plants!

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